The present invention relates to cellular radio communication systems.
Cellular radio communication systems consist of a base transceiver station which communicates with a number of, usually mobile, subsidiary transceiver stations with an area surrounding the base station and constituting a cell of the system.
Conventionally, cellular radio communication systems are categorized as macrocell, microcell or pico cell according to the nominal radius of the cells constituting the system. Macrocell systems have cells with radii of over 1 km, microcell systems have cells with radii in the range of 100 m to 1 km and picocell systems have cell radii in the range 30 m to 100 m. A form of cellular radio communication system with a still smaller cell size is coming into use and has been given the designation xe2x80x9cpersonalxe2x80x9d. Such systems have cell radii less than 30 m, and typically less than 3 m. A few personal cells may be considered together as a xe2x80x9cgroupxe2x80x9d cell.
In personal/groups cells the usage of individuals resources levels (area used over time, frequencies used, cell size, bandwidth allocated, and services) and interference are monitored by the system. This information may then be used to optimise the performance of the system (capacity level, resource usage, power).
In macro, micro and pico cell systems, the nominal sizes of the cells and the frequencies upon which the base stations operate are determined during the initial setting up and commissioning of the system concerned.
In personal cellular radio communication systems on the other hand, the cell size"" and its characteristic frequency may be assigned to a specific user of the system and not to a base station in a fixed location.
The present invention, although applicable to all types of cellular radio communication systems, is particularly useful in connection with personal cellular radio communication systems.
According to the present invention there is provided a method of optimising the operation of a cellular radio communication system, including the operations of monitoring the positions of services used and frequency of calls made by user stations within cells in a region of the cellular radio communication system, establishing a dynamic user profile data base related thereto, and varying the characteristics of the cells in the said region of the radio communication system in response to data derived from the user profile data base so as to allocate resources to the cells as a function of the demands made by the user stations within the cells.
The word xe2x80x9cdynamicxe2x80x9d is used to indicate that the information in the data base is updated regularly.
The said resources may include the sizes of the cells and/or the number of traffic channels and available within the cells. Preferably there is included also the operations of monitoring the level of interference within the cells in the said region of the cellular communication system, producing an interference probability distribution function related thereto, and routing calls to avoid those cells in which the levels of interference are highest.
There may be included also the operations of producing a location probability distribution function for specific users of the system so that calls initially routed to those cells where experience has shown that the specific users are most likely to be. Also, the handover sequences for those cells can be recorded in the user profile data base so that they can be initiated at the same time that a request for service is received by the base transceiver station of the cell concerned.
The above operations are applicable particularly in the case of the smallest cell size systems (pico and personal) because most users of such systems tend to remain in well defined positions, or to move only locally.